Other highlights in the September 17 issue of JNCI

A prostate-specific antigen doubling time (PSA-DT) of less than 3 months after treatment is associated with an increased risk of death from prostate cancer, according to a new study. Anthony V. D'Amico, M.D., Ph.D., of the Brigham and Women's Hospital in Boston, and his colleagues examined time to prostate cancer-specific mortality among 8,669 patients with localized or locally advanced prostate cancer who were treated with either surgery or radiation therapy. Patients whose PSA levels doubled in less than 3 months had a nearly 20-fold increase in risk of death from prostate cancer and a nearly 7-fold increase in risk of death from any cause. "We recommend that consideration be given to initiating androgen suppression therapy at the time of a PSA-defined recurrence," the authors conclude.

A new study suggests that a few risk factors account for a majority of esophageal and gastric cancers in the general population. These factors include smoking, being overweight, having gastroesophageal reflux (acid reflux), and consuming low amounts of fruits and vegetables. The study was conducted by Lawrence S. Engel, Ph.D., now at the Memorial Sloan-Kettering Cancer Center in New York, and his colleagues and involved 1143 patients with esophageal or gastric cancers and 695 healthy controls. "The rapid increase in the incidence of esophageal and gastric cardia adenocarcinomas appears to result from increases in the prevalence of several modifiable and interrelated risk factors," the authors conclude. "Efforts to reduce the prevalence of being overweight, having gastroesophageal reflux, and smoking and to improve diet could reverse this troubling cancer trend."

Vitamin E May Play a Role in the Development of Esophageal and Gastric Cancers

High serum levels of á-tocopherol, one of two major forms of vitamin E, are associated with a decreased risk of upper gastrointestinal cancers, a new study has found. Philip R. Taylor, M.D., Sc.D., of the National Cancer Institute, and his colleagues measured serum á- and ã-tocopherol levels in 1,072 patients with esophageal squamous cell carcinoma, gastric cardia cancer, or gastric noncardia cancer, and 1,053 healthy controls. High á-tocopherol levels were associated with a reduced risk of esophageal squamous cell carcinoma, but an increased risk of gastric noncardia cancer. Serum ã-tocopherol levels were not associated with the incidence of any of these cancers.

Inhibition of hMYCN oncogene expression is associated with a reduction in the incidence of neuroblastomas in mice, according to a new study. Neuroblastomas are childhood tumors of sympathetic nervous tissue. Catherine A. Burkhart, and Michelle Haber, Ph.D., of the Children's Cancer Institute Australia for Medical Research, and colleagues used antisense oligonucleotides to inhibit hMYCN expression in mouse models of neuroblastoma. Mice treated continuously with antisense oligonucleotides had a lower incidence of neuroblastomas and lower mean tumor mass than mice treated with control oligonucleotides. "Our results raise the possibility that hMYCN antisense therapy may ultimately be clinically useful in the treatment of childhood neuroblastoma," the authors conclude.

Researchers Address Questions about the Design of Dual-Label Microarrays

The rapid growth in the use of dual-label microarrays for measuring gene expression has generated many questions about how to design experiments that use this technology effectively. In a commentary, Kevin Dobbin, Ph.D., of the National Cancer Institute, discusses common methodologic questions that arise in designing dual-label microarray experiments and provides statistical answers to these questions, with a particular focus on how to select optimal designs for efficient identification of differentially expressed genes. The authors provide detailed examples of the statistical properties of different design options and their robustness, and they discuss the statistical issues related to sample selection, allocation and pooling of samples, pairing of samples for co-hybridization, changes in class definition, class discovery experiments, dye bias, and sample size.

Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.

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